FlexDelegate class

Flex delegate for running models that use SELECT_TF_OPS.

The Flex delegate enables TensorFlow operations that are not available as TFLite builtins. This is required for training models whose gradient ops cannot be expressed as builtins (e.g., Conv2D, BatchNormalization).

Supported on iOS, macOS, Linux and Windows. Not on Android: Android flex was removed in flutter_litert 4.0.0 because LiteRT 2.x has no flex delegate. There isAvailable is false and create throws. Reconvert the model to LiteRT built-in ops, or stay on flutter_litert 3.10.x with flutter_litert_flex 1.3.0.

Add flutter_litert_flex to your pubspec.yaml to bundle the native library on supported platforms:

dependencies:
  flutter_litert: ^4.1.0
  flutter_litert_flex: ^2.1.0

Then create the delegate. The async create works on every supported platform:

final flex = await FlexDelegate.create();
final options = InterpreterOptions();
options.addDelegate(flex);
final interpreter = Interpreter.fromFile(model, options: options);